1. Field of the Invention
The present invention relates to an electric power distribution device, in particular, to an electric power distribution device for supplying electric power to a stator coil that arranges on a motor-rotation axis centered circle.
2. Description of the Related Art
Recently, needs for reducing the fuel cost of a vehicle has become large, and for example, a development of the super-low fuel consumption hybrid vehicle is under development. Especially recently, a hybrid car with a motor assistance mechanism which assists an engine by a brushless DC motor when gathering speed is proposed.
The motor for use in the motor assistance mechanism includes a rotor directly coupled to a crankshaft of an engine, and a ring-shaped stator surrounding the rotor. The stator is composed by a lot of magnetic poles formed by coil a core, a stator holder for receiving the magnetic pole, and a concentrated electric power distribution device for supplying electricity to the coil intensively.
FIG. 13 shows a conventional concentrated electric power distribution device disclosed in Japanese published patent application No. 2003-134724. As shown in FIG. 13, the concentrated electric power distribution device includes three bus bars 22a, 22b, 22c corresponding to each layers of a motor, and an insulating holder 21 receiving the bus bars 22a, 22b, 22c in a manner the bus bars are insulated to each other.
As shown in FIG. 14, the bus bars 22a, 22b, 22c are formed by stamping a conductive metal plate 91 in a band shape, and bending the metal plate in a thickness direction thereof to form a substantially circular shape, where diameters of the bus bars are different from each other. Terminals 50v, 50u, 50w connected to a battery and tabs 41a, 41b, 41c connected to the coils of the stator are formed in a width direction at a far side from the insulating holder 21. Circular receiving grooves having the same radiuses as the bus bars 22a, 22b, 22c are formed on the insulating holder 21.
However, according to such a conventional concentrated power supply member, the bus bars 22a, 22b, 22c are curved in a length direction. Therefore, after stamping the metal plate, a bending machine bends the bars in whole lengths. Further, when curving the bus bars 22a, 22b, 22c by a press metal mold, it is necessary to divide the length direction into the plural for pressing. Therefore, a processing man-hour increases and it becomes a problem about the cost. Further, because the curving radiuses of the bus bars 22a, 22b, 22c are different, the bus bars 22a, 22b, 22c cannot be curved once. Further, two or more set of the bus bars 22a, 22b, 22c cannot arranged in a width direction of the metal plate 91. Therefore, the manpower and the production cost increases.
It is necessary to raise the processing accuracy when curving the bus bars 22a, 22b, 22c. If the curving radiuses of the bus bars 22a, 22b, 22c are different from those of the receiving grooves of the insulating holder 21, it is hard to receive the bus bars 22a, 22b, 22c in the receiving grooves of the insulating holder 21, and working ability decreases.
Accordingly, an object of the present invention is to provide an electric power distribution device with which the manpower of producing the bus bars can be reduced, and producing the bus bars at low cost.